I have no real interest in what the state has to say on the issue of marriage. Secular culture is going to do what it's going to do.
But what causes God to consider two people to be married? In light of all the marriage-confusion in our society at large and the church specifically, I think this question should be asked.
God has made it clear that one man can marry one woman. He's limited it to this. Genesis 2:24 tells us, "Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh." There are no other options.
So, if a man and a woman want to be married, what signals that they are married? What is required to make it so?
Does God require a public ceremony? It is interesting that all cultures of all time have both recognized marriage as an institution and have had some sort of ceremony to signal its beginning. We know that Jesus himself attended a wedding at Cana. However, does a ceremony have to occur? It does not seem to. Couples that go to a judge to get married or fly to Vegas to tie the knot are still considered married. I believe God sees them as so.
What about the act of sexual intercourse? Does this cause people to be married? Well, in scripture we see people having sex but not being married. In our culture people are fornicating left and right. No one considers this to cause marriage to occur.
So, what makes it so? If a couple simply lives together for a while, is this enough? Although some states might consider this to be some sort of "common-law" marriage, it does not appear that God recognizes it as such.
So what takes a couple from not being married to being married? We find the answer back in Genesis 2:24. Although the wording of the verse is directed to the male, it applies to both parties involved. There is a three-step process. First, they leave their parents. This is not necessarily a physical departure (in some cultures the young couple lives with one set of parents for quite some time). Instead, it describes a departure of identity. Second, upon leaving the parents the couple holds fast (clings) to one another. They become closer to one another than anyone else on earth. They hold on and don't let go. Third, they become one flesh. In many ways they go from being two people to one person. They are one unit. This describes much more than just physical union. It talks about a couple becoming one in covenant with each other, forsaking everyone else.
What we see described in 2:24 is usually accompanied by a public ceremony of some kind (a wedding). That's where the becoming one can be seen and declared publically. This seems appropriate. That's probably why it occurs in all cultures. However, it is not necessary.
The key is Genesis 2:24. It is where we learn what God thinks. It is by this verse that we see what makes a man and a woman married.
Interestingly, Jesus gives a commentary on the significance of 2:24. In Matthew 19:3-6 we read the following:
And Pharisees came up to him and tested him by asking, "Is it lawful to divorce one's wife for any cause?" He answered, "Have you not read that he who created them from the beginning made them male and female, and said, 'Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh'? So they are no longer two but one flesh. What therefore God has joined together, let not man separate."
This is not surprising since Jesus is God. He has stated early in the bible just what he considers important for a man and a woman to be married.
In the midst of our cultural marriage-confusion, we would do wise to keep Genesis 2:24 in mind.